An electrocardiograph is a device adapted to record the electrical activity of a patient's heart over time. The electrocardiograph includes one or more sensors or electrodes adapted for attachment to a patient and configured to sense electrical activity. The electrodes transmit electrical signals pertaining to the cardiac activity via a conductor such as a wire to a controller. The controller may generate a plot referred to as an electrocardiogram (ECG) based on the data from the electrodes.
In conventional ECG acquisition, one electrode is driven to a direct current (DC) potential such that the common-mode potential appearing at all of the other electrodes falls within the common-mode signal range of the ECG input amplifiers. The electrode may also be driven with a simple out-of-band tone in order to detect major lead failure conditions, such as an open circuit. However, this conventional ECG acquisition does not provide any additional information regarding the failure condition.